drivers/w1/w1_therm.c

   1 /*
   2  *      w1_therm.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the therms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <asm/types.h>
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/device.h>
  28 #include <linux/types.h>
  29 #include <linux/delay.h>
  30
  31 #include "w1.h"
  32 #include "w1_io.h"
  33 #include "w1_int.h"
  34 #include "w1_family.h"
  35
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
  39
  40 static u8 bad_roms[][9] = {
  41                                 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
  42                                 {}
  43                         };
  44
  45 static ssize_t w1_therm_read_name(struct device *, char *);
  46 static ssize_t w1_therm_read_temp(struct device *, char *);
  47 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
  48
  49 static struct w1_family_ops w1_therm_fops = {
  50         .rname = &w1_therm_read_name,
  51         .rbin = &w1_therm_read_bin,
  52         .rval = &w1_therm_read_temp,
  53         .rvalname = "temp1_input",
  54 };
  55
  56 static ssize_t w1_therm_read_name(struct device *dev, char *buf)
  57 {
  58         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  59
  60         return sprintf(buf, "%s\n", sl->name);
  61 }
  62
  63 static inline int w1_convert_temp(u8 rom[9])
  64 {
  65         int t, h;
  66
  67         if (rom[1] == 0)
  68                 t = ((s32)rom[0] >> 1)*1000;
  69         else
  70                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
  71
  72         t -= 250;
  73         h = 1000*((s32)rom[7] - (s32)rom[6]);
  74         h /= (s32)rom[7];
  75         t += h;
  76
  77         return t;
  78 }
  79
  80 static ssize_t w1_therm_read_temp(struct device *dev, char *buf)
  81 {
  82         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  83
  84         return sprintf(buf, "%d\n", w1_convert_temp(sl->rom));
  85 }
  86
  87 static int w1_therm_check_rom(u8 rom[9])
  88 {
  89         int i;
  90
  91         for (i=0; i<sizeof(bad_roms)/9; ++i)
  92                 if (!memcmp(bad_roms[i], rom, 9))
  93                         return 1;
  94
  95         return 0;
  96 }
  97
  98 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
  99 {
 100         struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
 101                                                 struct w1_slave, dev);
 102         struct w1_master *dev = sl->master;
 103         u8 rom[9], crc, verdict;
 104         int i, max_trying = 10;
 105
 106         atomic_inc(&sl->refcnt);
 107         smp_mb__after_atomic_inc();
 108         if (down_interruptible(&sl->master->mutex)) {
 109                 count = 0;
 110                 goto out_dec;
 111         }
 112
 113         if (off > W1_SLAVE_DATA_SIZE) {
 114                 count = 0;
 115                 goto out;
 116         }
 117         if (off + count > W1_SLAVE_DATA_SIZE) {
 118                 count = 0;
 119                 goto out;
 120         }
 121
 122         memset(buf, 0, count);
 123         memset(rom, 0, sizeof(rom));
 124
 125         count = 0;
 126         verdict = 0;
 127         crc = 0;
 128
 129         while (max_trying--) {
 130                 if (!w1_reset_bus (dev)) {
 131                         int count = 0;
 132                         u8 match[9] = {W1_MATCH_ROM, };
 133                         unsigned int tm = 750;
 134
 135                         memcpy(&match[1], (u64 *) & sl->reg_num, 8);
 136
 137                         w1_write_block(dev, match, 9);
 138
 139                         w1_write_8(dev, W1_CONVERT_TEMP);
 140
 141                         while (tm) {
 142                                 tm = msleep_interruptible(tm);
 143                                 if (signal_pending(current))
 144                                         flush_signals(current);
 145                         }
 146
 147                         if (!w1_reset_bus (dev)) {
 148                                 w1_write_block(dev, match, 9);
 149
 150                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 151                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 152                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 153                                 }
 154
 155                                 crc = w1_calc_crc8(rom, 8);
 156
 157                                 if (rom[8] == crc && rom[0])
 158                                         verdict = 1;
 159
 160                         }
 161                 }
 162
 163                 if (!w1_therm_check_rom(rom))
 164                         break;
 165         }
 166
 167         for (i = 0; i < 9; ++i)
 168                 count += sprintf(buf + count, "%02x ", rom[i]);
 169         count += sprintf(buf + count, ": crc=%02x %s\n",
 170                            crc, (verdict) ? "YES" : "NO");
 171         if (verdict)
 172                 memcpy(sl->rom, rom, sizeof(sl->rom));
 173         else
 174                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 175
 176         for (i = 0; i < 9; ++i)
 177                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 178
 179         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom));
 180 out:
 181         up(&dev->mutex);
 182 out_dec:
 183         smp_mb__before_atomic_inc();
 184         atomic_dec(&sl->refcnt);
 185
 186         return count;
 187 }
 188
 189 static struct w1_family w1_therm_family = {
 190         .fid = W1_FAMILY_THERM,
 191         .fops = &w1_therm_fops,
 192 };
 193
 194 static int __init w1_therm_init(void)
 195 {
 196         return w1_register_family(&w1_therm_family);
 197 }
 198
 199 static void __exit w1_therm_fini(void)
 200 {
 201         w1_unregister_family(&w1_therm_family);
 202 }
 203
 204 module_init(w1_therm_init);
 205 module_exit(w1_therm_fini);